Some embodiments disclosed herein relate to a medical connector having a backflow resistance module configured to prevent fluid from being drawn into the connector when a backflow inducing event occurs. In some embodiments, the backflow resistance module can include a variable-volume chamber configured to change in volume in response to a backflow-inducing event and a check valve configured to resist backflow. In some embodiments, the medical connector can include a fluid diverter configured to direct fluid flowing through the medical connector into the variable volume chamber to prevent fluid stagnation therein. In some embodiments, the medical connector includes a body member, a base member, a seal member, a support member, and a valve member.